The subject of this invention is a seat padding, particularly for vehicle seats, with at least one core part made of an elastic plastic foam.
Seat paddings of this type are presently often used for vehicle seats. The core part generally consists of a polyurethane (PUR cold foam) molding.
For seat paddings of high-end vehicles, moldings from a mixture of natural fibers such as coconut fiber, animal hair, etc. are also used, the fibers being treated with binding agents, particularly latex, and formed to a cushion part. Such a fiber/binding-agent material is also known as xe2x80x9crubber hairxe2x80x9d.
The two known types of seat paddings have advantages and disadvantages. While plastic moldings are light, but little permeable for air, cushion parts from rubber hair have a considerably higher weight, but can be easily vented due to their high air permeability.
For seat paddings it is furthermore desired to shape certain zones of the seat area differently to support different seat pressures. For example, a higher seat pressure must be supported in the area of the human ischial tuberosities than, say, in the area of the thighs. Using a support area that is too small, however, would impair the seat user""s comfort because a high seat pressure may negatively affect the blood supply to the legs. A bad seat pressure distribution may often lead to numb legs. To avoid these problems, cushion parts made of so-called two-zone foam have also been introduced. These cushion parts are characterized by harder or softer foam in the appropriate partial areas. However, the production of such cushion parts is difficult and cost-intensive, and often the desired effect is not achieved because the fine adjustment of the seat pressure distribution requires extremely high effort.
The objective of this invention is to create a cushion part of the type as described above, whose seating area can be adjusted highly accurately to the desired seating comfort in a simple and inexpensive way.
The invention achieves this by channel-like grooves on the top side of the core part facing a seat surface, with the core part entirely made of one foam material only. These grooves running through the seat surface cause zonal weakenings, and by designing a certain layout of these grooves, the intermediate, remaining partial surfaces of the core part can be given different supporting strengths. This means that partial surfaces with different surface areas can be created. Small, closely adjacent partial surfaces produce relatively soft part sections while larger partial surfaces produce an overall harder section. This provides a simple means to shape the entire seat surface according to the pressure conditions required. This results in a good, ergonomic body support, while at the same time providing a soft and comfortable seating experience. Mainly the channel-like grooves and the resulting remaining partial surfaces of the core part are shaped according to the human anatomy in the seating area to achieve an optimal seat pressure distribution.
The invention enables in principle even an individual adjustment of each seat to the seating requirements of each user by giving the channel-like grooves a preferably empirically determined layout, which is identical for all users, and filling the grooves at least partly with inserts. These inserts preferably consist of a material that is comparatively harder than the core part. The inserts pass the seat pressure on to the adjacent padding material.
To achieve a smooth transition of the pressure distribution from relatively harder zones to relatively softer zones, it is advantageous to cover the grooved core part surface facing the seat user with a relatively thin overlay. This overlay preferably consists of the above-mentioned xe2x80x9crubber hairxe2x80x9d.
Another advantage of this invention is the considerably improved venting condition, because the channel-like grooves allow at least a partial air circulation. Especially in combination with the rubber hair overlay, it could be shown that the highly air-permeable overlay allows an excellent removal of humidity. The continuous movements of the seat user on the seat padding during a ride cause a pump effect producing an airflow in the channel-like groove system of the core part transporting the humid airxe2x80x94mainly through specially provided, vertical openings in the foam cushion partxe2x80x94to the outside without requiring the use of additional fans.
However, the invention also allows an additional active ventilation by at least one fan. The fan should then preferably be located below the seat padding providing a vertical airflow with a suction or pressure effect.
Additional advantageous design features are contained in the sub-claims and the description below.